Wednesday, September 24, 2008

This is extremely confusing to me. There's a report at Edmunds saying the Volt gas engine is not used to recharge the battery pack. That means the Volt is not a series hybrid.

In contrast to popular (and our) impression, once a driver uses up his 40 or so miles of electric power, the 1.4-liter gas engine generates electricity to power the electric drive motor, but does not recharge the batteries. After the 40 or so miles, the battery becomes 400 pounds of uselessness, at least until the owner can plug the car into the electrical grid for a recharge. This means that regardless of how far one drives the Volt, the driver will only ever get up to 40 miles of electric-only range.

That's completely shocking to me. I've been talking about the Chevy Volt since the prototype was unveiled and it was always my impression the Volt was a series hybrid and the gas engine would not power the vehicle. It would only recharge the battery pack.

How can the battery pack not get recharged? Won't the Volt have regenerating breaks? Why would it not go back into electric mode?

A release from the day of the production prototype's reveal reads, "a gasoline/E85-powered engine generator seamlessly provides electricity to power the Volt's electric drive unit while simultaneously sustaining the charge of the battery." And by "sustaining" GM says that it means only that no additional power is drained from the batteries. Get it?

Oh, alright, I guess I understand now. This quote mean the gas engine 'sustains' the battery pack, allowing it to continue to power the electric motor, which in turn lets the electric motor continue to move the sedan, the way we think it does.

I can understand that. The battery pack is best charged by plugging it in. By keeping the battery pack at a certain level, you help it last longer.

But I guess I never thought it would last 40 miles and that would be that. I would have thought the battery could get charged up and switch back into electric mode.

1 comment:

Anonymous
said...

In simple terms the video sais "when the battery power runs out the gas engine supplies the electrical power for the electrical engine which is driving the car".

That is the definition of a series hybrid, a gas engine(or any other power source) turning a generator which provides electrical power for an electrical motor. "leftover" electrical energy can be stored in a battery.

"How can the battery pack not get recharged?"

The engine will be busy keeping the car moving and might not be able to charge the battery while driving. I like to think that the gas engine will give power not used by the el. engine back to the batteries but i don't know if that is the case.

In city driving, with all the stop and go driving that includes, the gas engine should have plenty of opportunities to charge the batteries. The video mentions a buffer zone it will keep the battery within. Allthough they don't use the term charging, this statement makes me think that some charging is going on while driving. I do think the car use some of this extra battery power during acceleration, or the car would be "slow of the line"

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